• 한국환경보건학회지
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• 제40권6호
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• pp.469-476
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• 2014

Objectives: The purpose of this study was to identify the stains causing infections in dental clinics by analyzing bacterial contamination, as well as to suggest improvements for infection control in dental clinics. Methods: In this study, a questionnaire survey of 47 dental hospitals and clinics located in Gyeonggi-do and Incheon, South Korea was administered from June 2013 to September 2013 and used to investigate the practice rates of infection control by dental hygienists and to analyze the bacterial contamination levels in dental offices. Results: In the studied institutions, the bacterial contamination levels of water lines were $20.9{\times}10^3$ colony forming units (CFU)/mL for three-way syringes, $12.7{\times}10^3CFU/mL$ for high-speed handpieces and $9.8{\times}10^3CFU/mL$ for gargling water. The bacterial contamination levels of surfaces were $44.9{\times}10^3CFU/mL$ in cuspidors, higher than in unit chairs ($2.9{\times}10^3CFU/mL$) and light handles ($6.7{\times}10^3CFU/mL$). The mean bacterial cell count of water lines and surfaces was relatively high in all establishments founded 11 years ago or more, and the mean bacterial cell count of waterline handpieces was $6.27{\times}10^3CFU/mL$ in establishments founded between one and five years ago, $11.16{\times}10^3CFU/mL$ six to ten years ago and $20.04{\times}10^3CFU/mL$ 11 years ago or more, which suggests that earlier foundation is associated with higher bacterial contamination levels with a statistical difference (p<0.01). Similarly, the mean bacterial cell count of cuspidors using water from water lines was also $70.16{\times}10^3CFU/mL$ in at least 11-year-old establishments, statistically significantly higher among in one- to five-year-old ($4.61{\times}10^3CFU/mL$) and six- to ten-year-old clinics ($47.89{\times}10^3CFU/mL$) (p<0.05). Conclusion: This study may be utilized to improve the bacterial contamination levels in dental offices by controlling the characteristics and environmental factors of dental offices that affect the microbial contamination of waterlines and surfaces in such institutions.

• Fisheries and Aquatic Sciences
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• 제18권3호
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• pp.235-240
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• 2015

Seasonal variation in the prevalence of norovirus in oysters Crassostrea gigas was investigated and compared to levels of Escherichia coli, a fecal indicator in oysters. Oysters were collected from Iwon-myeon, Taean-gun, Korea, a primary production area for European Union export of oysters between 2013 and 2014. We observed seasonality in the prevalence of norovirus in oysters, with a higher prevalence and viral load detected during winter months. Oysters taken from production areas that complied with the European Union standard for raw consumption (< 230 MPN/100 g of E. coli) had 22.1% of the samples test positive for norovirus (15/68 samples). However, norovirus was not detected in any of the samples (0%, 0/4 samples) that were collected from production sites that exceeded the standard fecal contamination level for raw consumption (> 230 MPN/100 g of E. coli). These results indicated that there is a negative correlation between the prevalence of norovirus and high levels of E. coli in oysters. Therefore, our results suggest that current food safety guidelines using only a bacterial fecal contamination indicator, E. coli, may not adequately assess shellfish production areas for viral and bacterial contamination.

• 한국작물학회:학술대회논문집
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• 한국작물학회 2017년도 9th Asian Crop Science Association conference
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• pp.245-245
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• 2017

Heavy metal pollution of agricultural soils affects land productivity and has impact on the quality of surrounding ecosystem. Soil microbial community parameters are used as reliable indices for assessing quality of agricultural lands under metal stress. This study investigated bacterial community structure of polluted and undisturbed paddy soils to elucidate soil factors that are related to alteration of bacterial communities under conditions of metal pollution. No obvious differences in the richness or diversity of bacterial communities were observed between samples from polluted and control areas. The bacterial communities of three locations were distinct from one another, and each location possessed distinctive set of bacterial phylotypes. The abundances of several phyla and genera differed significantly between study locations. Variation of bacterial community was mostly related to soil general properties at phylum level while at finer taxonomic levels concentrations of arsenic and lead were significant factors. According to results of bacterial community functional prediction, the soil bacterial communities of metal polluted locations were characterized by more abundant DNA replication and repair, translation, transcription and nucleotide metabolism pathway enzymes while amino acid and lipid metabolism as well as xenobiotic biodegradation potential was reduced.Our results suggest that the soil microbial communities had adapted to the elevated metal concentrations in the polluted soils as evidenced by changes in relative abundances of particular groups of microorganisms at different taxonomic resolution levels, and by altered functional potential of the microbial communities.

• 한국콘텐츠학회:학술대회논문집
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• 한국콘텐츠학회 2009년도 춘계 종합학술대회 논문집
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• pp.1150-1158
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• 2009

현재 영상의학과에서 사용되는 촬영장비는 질환을 가지고 있는 환자와의 접촉이 불가피 하기 때문에 병원균이 존재 할 수밖에 없다. 따라서 영상의학과 촬영실에서의 세균 오염도를 측정하고, 검출된 세균들을 소독(물, Tissue Cleaner, 70% 알코올)하여 소독 전 후 세균의 감소율을 비교함으로써 병원감염예방에 있어 소독제 사용의 중요성과 병원감염관리의 인식을 높이고자 한다. 영상의학과 촬영실에서의 세균 오염도를 측정 하였을 때 여러 가지 세균들이 검출되었다. 영상의학과 촬영실내를 소독할 때 물이나 Tissue Cleaner, 환기 보다는 70% Alcohol을 사용하여 소독을 실시하는 것이 세균 사멸 및 병원감염 예방부분에 있어 효과적임을 알 수 있었다. 따라서 세균을 사멸시키기 위해 보다 좋은 소독제를 개발하여야 하며, 병원 내 각종 의료 장비는 언제나 오염될 가능성이 있으므로 기구에 대한 소독 및 멸균을 실시하여 병원감염으로 인해 환자에게 2차 감염을 유발되지 않도록 노력해야 할 것이다.

• 한국식품저장유통학회지
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• 제20권3호
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• pp.323-329
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• 2013

딸기는 다양한 효능을 보일 뿐만아니라 맛과 영양까지 뛰어나 많은 사람들이 선호하는 대표적인 즉석섭취 농산물 중의 하나이다. 따라서 딸기의 안전성에 대한 관심이 매우 높다. 본 연구는 딸기의 생물학적 안전성을 평가하기 위하여 논산시내 12개 딸기 농장에서 채취한 1,020개의 표본(열매, 줄기, 잎 각각 340개씩)을 대상으로, 재배방식(양액재배, 무농약재배, 유기농재배) 및 딸기의 부위에 따른 총호기성균, 대장균군/대장균을 정량적 분석하였다. 또한 식중독 유발세균인황색포도상구균, Salmonella spp, L. monocytogenes, E. coli O157:H7 오염 여부를 정량 혹은 정성 분석하였다. 딸기 표본의 총호기성균 수는 2.3~6.8 ${\log}_{10}$ CFU/g 범위이었으며, 대장균군은 전체 표본의 14.2%에서 검출되었고 양성 표본의 대장균군 수는 2.1-4.5 ${\log}_{10}$ CFU/g 범위이었다. 대장균은 전체 표본중 1.0%에서 검출되었고, 양성 표본의 대장균 수는 2.1-2.8 ${\log}_{10}$ CFU/g 범위이었다. 딸기의 재배방식별로 분석시, 총호기성균 및 대장균군의 수는 양액재배 혹은 무농약재배에 비하여 유기농재배에서 더 많이 검출되었으나(p<0.05), 대장균은 무농약재배와 유기농재배에서 유사하게 검출되었고 영양재배에서는 검출되지 않았다. 딸기를 3개 부위(열매, 줄기 및 잎)로 나누어 호기성균 및 대장균군/대장균 수를 분석시, 이들간 통계적 유의성은 없었다. 또한 딸기에 부착되어 있는 식중독 유발 세균을 조사한 결과, 1,020개의 표본중에서 유기농재배 농가 표본 2개에서 황색포도상구균이 검출되었으며 그 외의 Salmonella spp., Listeria spp., E. coli 0157:H7은 모든 표본에서 검출되지 않았다. 이상의 결과로 보아, 딸기의 재배 방식에 따라 위생지표 미생물의 오염에 차이가 있을 수 있으므로, 재배 방식에 적합한 세균 오염 저감화 대책이 요구됨을 시사하겠다.

• Journal of Nutrition and Health
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• 제4권3호
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• pp.13-25
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• 1971

During a period from October 1st to November 15th in 1971, We made a survey on hygienic status of kitchen utensils used at 270 college student's home in 9 districts of Seoul city. The results obtained could be summarized as follows. In bacteriological study on the kitchen utensils 20.7% of them revealed contaminations with general bacterial counts of over 100/m1 and 20.0% of them with coliform bacteria. It was probable that degrees of bacterial contamination of the kitchen utensils were chiefly attributable to levels of education of housewives and living standard of individual household. Factors that were presumed to be directly responsible for the contamination were sources and storage of water and methods of washing the utensils. One of the major sources of contamination was derived from the use of a piece of cloth (Hangjoo) to wipe up the utensils after soashing. Hygienic treatment of Hangjoo in urgently needed. Otherwise, it is desirable not to used the Hangjoo and leave the utensils dry after washing them with boiling water.

• Reproductive and Developmental Biology
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• 제37권4호
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• pp.213-217
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• 2013

The objective of this study was to investigate the effect of bacterial contamination on elapsed time after preservation on boar semen. Known numbers of Escherichia coli (E. coli) were inoculated to freshly ejaculated semen and sperm parameters such as viability, motility, agglutination, acrosome integrity and hypo-osmotic swelling test were performed during 7 days of liquid preservation. Semen samples were prepared using antibiotic free BTS extender and 4 different levels of E. coli were treated to semen with following concentrations; 3,000, 5,000, 7,000, 10,000 CFU/ml of sperms. Semen samples were preserved at $17^{\circ}C$ for 7 days in semen storage until analyzed. Aliquots were subjected to measure the sperm viability, motility and agglutination using computer assisted sperm analysis (CASA) system, acrosome integrity was performed using chlortetracycline (CTC) staining method and hypo-osmotic swelling test was performed using hypotonic solution from day 1 (day of semen collection) to 7. Detrimental effects on sperm motility and viability were observed 3 days after preservation at the level of 5,000 CFU/ml (p<0.05). Percentage of sperm abnormality was higher (p<0.05) in over 5,000 CFU/ml groups. Sperm agglutination rate was also significantly higher (p<0.05) in groups of 5,000 and 7,000 CFU/ml. The rate of acrosome reacted sperm was higher as preservation time goes in all the samples but the pattern was clearly higher among E. coli contaminated groups (p<0.05). The sperm membrane integrity in terms of hypo-osmotic test, E. coli affects little compared to other sperm parameters. The deleterious effects observed due to the bacterial contamination in semen suggest that importance of hygiene protocol to minimize the bacterial contamination during semen collection and processing.

• International Journal of Oral Biology
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• 제39권3호
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• pp.137-143
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• 2014

Dental professionals are repeatedly exposed to many microorganisms present in both blood and saliva. Thus, dental professionals are at a greater risk of acquiring and spreading infections, and the implementation of infections control guidelines is necessary. Cellular phones have become a necessary device for communicating in hospitals. Cellular phones contaminated with bacteria may serve as a fomite in the transmission of pathogens by the hands of medical personnel. Nevertheless, studies about rate and levels of bacterial contamination of cellular phones have been extremely limited with regards to dental personnel. The purpose of this study was to identify bacterial flora on the cellular phones of dentists by a molecular biological method using the 16S rRNA cloning and sequencing method. We acquired total 200 clones from dentists' cell phones and identified the bacterial species. Pseudomonas (34.6%), Lactobacillus (18.5%), Azomonas (11.5%), and Janthinobacterium (6%) were the dominant genera on dentists' cell phones. The oral bacteria identified were Anaerococcus lactolyticus, Gibbsiella dentisursi, Lactobacills leiae, Streptococcus mitis, Streptococcus oligofermentans, and Streptococcus sanguinis. Pathogenic bacteria and opportunistic pathogens such as Carnobacterium funditum, Raoultella planticola, Shigella flexneri, Lactobacillus iners, Staphylococcus aureus, and Staphylococcus epidermidis were also identified.

• The Journal of Advanced Prosthodontics
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• 제14권5호
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• pp.273-284
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• 2022

PURPOSE. Computer-aided design and manufacturing (CAD-CAM) of implant abutments has been shown to result in surface contamination from site-specific milling and fabrication processes. If not removed, these contaminants can have a potentially adverse effect and may trigger inflammatory responses of the peri-implant tissues. The aim of the present study was to evaluate the bacterial disinfection and cleaning efficacy of ultrasonic reprocessing in approved disinfectants to reduce the microbial load of CAD-CAM abutments. MATERIALS AND METHODS. Four different types of custom implant abutments (total N = 32) with eight specimens in each test group (type I to IV) were CAD-CAM manufactured. In two separate contamination experiments, specimens were contaminated with heparinized sheep blood alone and with heparinized sheep blood and the test bacterium Enterococcus faecium. Abutments in the test group were processed according to a three-stage ultrasonic protocol and assessed qualitatively and quantitatively by determination of residual protein. Ultrasonicated specimens contaminated with sheep blood and E. faecium were additionally eluted and the dilutions were incubated on agar plates for seven days. The determined bacterial counts were expressed as colony-forming units (CFU). RESULTS. Ultrasonic reprocessing resulted in a substantial decrease in residual bacterial protein to less than 80 ㎍ and a reduction in microbiota of more than 7 log levels of CFU for all abutment types, exceeding the effect required for disinfection. CONCLUSION. A three-stage ultrasonic cleaning and disinfection protocol results in effective bacterial decontamination. The procedure is reproducible and complies with the standardized reprocessing and disinfection specifications for one- or two-piece CAD-CAM implant abutments.

• 한국식품저장유통학회지
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• 제18권1호
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• pp.7-12
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• 2011

파프리카(Capsicum annuum var. angulosum)는 우리나라의 대표적인 수출농산물로서 지속적인 수출확대를 위해서는 안전성 확보가 중요하다. 지금까지 수출과채류의 생물학적 위해요소에 대한 연구는 많이 이루어 지지 않았다. 본 연구는 우리나라의 대표적인 수출 농산물인 파프리카를 대상으로 미생물오염실태를 모니터링하고, 보관온도에 따른 세균오염도 변화를 분석하였다. 파프리카의 평균 총호 기성균 수는 $2.3{\pm}0.3$ log CFU/g이었으며, 대장균군은 발견되지 않았다. 파프리카에서는 황색포도상구균이 발견되지 않았으며, 또한 Salmonella spp., Listeria spp. 및 E. coli O157:H7도 검출되지 않았다. 파프리카를 상온 및 $4^{\circ}C$에 각각 보관후 20일동안 세균 오염도를 측정한 결과, 상온에 보관시 총호기성균 수는 구입 14~16일에 가장 많이 증가하 였으나(4배 이상), $4^{\circ}C$에 보관시에는 세균 수 증가가 완만하였다. 대장균군은 상온에서 2회 검출되었으나, $4^{\circ}C$에서는 검출되지 않았다. 이상의 결과로 보아, 수출용 파프리카는 생물학적으로 안전하였으나, 상온에 장기간 보관시 유해미생물의 오염 가능성이 있으므로 유통과정중 철저한 위생관리가 요구된다.